[CI] Try introducing isort. (#3495)

vllm/engine/async_llm_engine.py

@@ -2,17 +2,17 @@ import asyncio
 import os
 import time
 from functools import partial
-from typing import (Callable, Dict, Iterable, List, Optional, Set, Tuple, Type,
-                    Union, AsyncIterator)
+from typing import (AsyncIterator, Callable, Dict, Iterable, List, Optional,
+                    Set, Tuple, Type, Union)
 
 from transformers import PreTrainedTokenizer
 
-from vllm.lora.request import LoRARequest
 from vllm.config import ModelConfig
 from vllm.engine.arg_utils import AsyncEngineArgs
 from vllm.engine.llm_engine import LLMEngine
 from vllm.engine.ray_utils import initialize_ray_cluster, ray
 from vllm.logger import init_logger
+from vllm.lora.request import LoRARequest
 from vllm.outputs import RequestOutput
 from vllm.sampling_params import SamplingParams